This invention is concerned with a composite yarn and a carpet tufted thereby, having durable antistatic properties and an excellent appearance.
A carpet, when used especially at low humidity, has an undesirable tendency to build up a static charge in itself as well as the persons who walk thereover, which can cause such electrostatic troubles as shocks to the body and promotion of soiling of the carpet. For the purpose of solving this problem, it has been proposed to incorporate in the surface layer of the carpet an electrically conductive yarn prepared by twisting a pile yarn with a monofilament having an electrically conductive coating thereon (U.S. Pat. No. 3,582,445). However, since the electrically conductive coated filament is partially exposed at surface of the carpet, there occur problems that the coating is liable to be worn away or be separated from the filament by direct contact with the walker in a short time, and that a surface appearance of the carpet is inferior owing to a black or brown coloration of the coating.
Further, it has been proposed to wrap a fine metallic filament with organic and glass fibers (Modern Textile Magazine, May 1966, page 73). However, there arise problems in connection with their blending and processing as well as in the feel or texture of the products obtained, because the textile fibers which are usually used in carpets are essentially dissimilar in character to the metallic fibers.
Furthermore, Japanese Patent Application Laid-open No. 57200/1974 teaches covering a metal-plated fiber with a covering yarn. However, the metal-plated fiber cannot be employed for the carpet, because a metal layer is readily separated from the fiber on use under heavy treading conditions such that the carpet is worn and as the result, antistatic properties of the carpet rapidly deteriorates.